The Allen brothers had founded Houston because the bayou offered access both to the cotton, timber and produce of inland farmers and planters and, via Galveston Bay, to the sea. Before railways and hardtopped roads dominated transportation, the bayou served personal as well as commercial transportation. When the city's roads were mired in mud deep enough to drown a mule, Houstonians who wanted to shop in nearby Harrisburg went there by boat. In an 1891 bird's-eye map of Houston, an artist drew the bayou as the most prominent geological feature of this flat coastal city. He found the bayou far more complex and interesting than the grid of streets lining its south bank.

Industry and business grew along the shores of the bayou. From its banks near the center of town, 19th-century brick companies mined red clay used to construct Houston's first buildings; timber companies floated logs down it and sawmills used its water power to cut the logs into lumber. The most important street in town was Commerce, which ran closest to the wharves from which planters shipped their cotton to manufacturers in England.

Not all this attention, though, was benign. Some of the businesses polluted the bayou. A slaughterhouse situated just west of town had to be ordered to move east and dump its offal downstream from the city. The sawmills were forbidden to unload sawdust in the stream. Erosion from the cut-down forests and small farms to the west silted the bayou and muddied its waters. But as jobs were created in the eastern end of the city, the western banks of the bayou were abandoned to forests again, and the waters ran clear.

The natural beauty of the bayou was not lost on Will and Ima Hogg, who helped foster Houston's westward expansion. In 1929 "Miss Ima" built the Bayou Bend mansion to house her collection of American antiques, and in 1930 her brother started the River Oaks development and country club on the south bank. Further west, Memorial Drive ran parallel to the curves of the bayou and brought more development and erosion with it. But as the development continued, the city failed to keep pace with the demands on its sewage treatment plants, which backed up during heavy rains. Eager to hold down taxes, politicians failed to add sewage treatment capacity as the city grew. By the 1960s, the western part of Buffalo Bayou stank of sewage from its wealthiest neighborhoods, and the Ship Channel into which it fed consisted of a poisonous soup of petrochemicals from the industries that lined its banks. After being born on the bayou, it looked like Houston had decided on a little patricide. It was killing its own parent.

On the morning that I settled into the bayou's western reaches, the flow of water was particularly good, because the Army Corps of Engineers was releasing water from the Barker dam. The water was greenish brown in color with visibility of less than a foot. But it smelled fine, and it was cool as it lapped into the bottom of the kayak and drenched my shorts. Within seconds, the corporate parking lot from which I had launched dropped from view, and the green canopy of trees embraced the little craft. A dragonfly settled on the bow to hitchhike for a ways. A hundred yards downstream I heard a splashing on the bank and pulled over to investigate. A pair of copulating frogs sat on the mud, the smaller male on top of the bigger female, making an almost seamless, clumsy, unified animal. Then I saw another pair, and another. I had stumbled into a frog rut. I left them in peace.

The western end of Buffalo Bayou runs for about three miles through a greenbelt county park that's lined with footpaths and jogging trails. The park occupies at least part of the floodplain and helps prevent erosion caused by encroaching development. It's named for the mother protector of Buffalo Bayou, Texas Parks and Wildlife Commissioner Terry Hershey.

In 1966, Hershey was headed to a party with some friends, and she was seething with anger. The Harris County Flood Control District was clearing all the trees from a nine-acre tract of land near the bayou at Chimney Rock. This was in preparation for straightening the channel and paving it with concrete. One of Hershey's friends said that he and a few other prominent Houston businessmen had formed an association to fight such plans. They had watched as the Corps already turned Brays and White Oaks bayous into concrete-lined ditches, and they didn't want to stand by passively while the same thing happened to Buffalo Bayou. Well, Hershey, told her friend, it was happening, and wasn't it time for the Buffalo Bayou Preservation Association to have another meeting?

The Corps had not decided to channelize the bayous all on its own. After disastrous downtown floods in 1929 and 1935, the city and county leadership had assembled a dramatic pictorial of the flood damage called "Wild River" and petitioned the Texas Legislature and the U.S. Congress for help. In 1937, the Legislature authorized the creation of the Harris County Flood Control District and gave it permission to levy property taxes through the Commissioners Court. The main purpose of the district was to leverage federal money through the Army Corps of Engineers. During World War II, the Corps built the Addicks and Barker reservoirs, which were designed to impound enough water upstream to prevent flooding downtown.